144 DOC. 140 NOVEMBER 1915 140. From David Hilbert [Göttingen, 13 November 1915][1] Dear Colleague, Actually, I first wanted to think of a very palpable application for physicists, namely reliable relations between the physical constants, before obliging with my axiomatic solution to your great problem. But since you are so interested, I would like to lay out my th[eory] in very complete detail on the coming Tuesday, that is, the day after the day after tomorrow (the 16th of this mo.).[2] I find it ideally handsome math[ematically] and absolutely compelling according to ax- iom[atic] meth[od], even to the extent that not quite transparent calculations do not occur at all and therefore rely on its factuality.[3] As a result of a gen. math. law, the (generalized Maxwellian) electrody. eqs. appear as a math. consequence of the gravitation eqs., such that gravitation and electrodynamics are actually nothing different at all.[4] Furthermore, my energy concept forms the basis:[5] E = S(ests + eihtih), which is likewise a general invariant, and from this then also follow from a very simple axiom the 4 missing “space-time equations” es = 0. I derived most pleasure in the discovery already discussed with Sommerfeld that normal electrical energy results when a specific absolute invariant is differentiated from the gravitation potentials and then g is set = 0.1.-[6] My request is thus to come for Tuesday. You can arrive at 3 or 1/2 past 5. The Math. Soc. meets at 6 o’clock in the auditorium building. My wife[7] and I would be very pleased if you stayed with us. It would be better still if you came already on Monday, since we have the phys. colloquium on Monday, 6 o’clock, at the phys. institute. With all good wishes and in the hope of soon meeting again, yours, Hilbert. As far as I understand your new pap[er], the solution giv[en] by you is entirely different from mine, especially since my es’s must also necessarily contain the electrical potential.[8] Document description: “Continuation on Sheet I with the invitation to come for Tues- day, 6 o’clock. Best regards, H.”